Scavenge oil system

ABSTRACT

The scavenge oil system disclosing the invention has a scavenge oil outlet located at the bottom of a blower housing whereby lubricating oil can flow thereto by gravity in most attitudinal positions of the housing. When the blower housing is in an attitude that a portion thereof, such as the rear, is at a level lower than the scavenge oil outlet, a scavenge pump, having an impeller driven by the blower shaft, is rendered effectively operable by having an inlet beneath the level of oil at the rear of the housing and the scavenge pump pumps the oil to a higher level whereby it may flow from the housing by gravity through either the scavenge oil outlet of the housing or through other passages. The scavenge oil system utilizes passages for oil flow formed as cored passages in the wall of the blower housing to minimize cost and weight addition to the blower and minimizes the power demands on the blower drive, since the scavenge pump will run dry in most attitudes of the blower and will only require power when effectively operating to pump oil to a higher level.

This a division of application Ser. No. 784,325 filed Oct. 3, 1985, nowU.S. Pat. No. 4,683,984

TECHNICAL FIELD

This invention pertains to a scavenge oil system for scavenging oil froma housing having a number of lubricated components and which can bepositioned in a number of different attitudes. In at least one of saidattitudes, oil cannot flow by gravity to a scavenge oil outlet at thebottom of the housing.

More particularly, power plants for certain aircraft utilize blowers aseither an inlet particle separator or to blow air through an oil cooler,thus cooling the oil, with the blower mountable to either the top or theside of a gearbox. The blower has a housing with various componentsrequiring lubrication, such as a gear mesh, bearings, splines and adynamic face seal and lubricating oil is directed to those components.The blower can be in any one of several different attitudes whereingravity flow of the lubricating oil is sufficient to have the oil reachthe scavenge oil outlet; however, in at least one attitude of theblower, the scavenge oil outlet is above a part of the housing which cancollect lubricating oil which flows thereto by gravity. The inventondisclosed herein provides for scavenging oil in the last-mentionedsituation by the provision of a scavenge pump positioned to pump oilfrom that part of the housing to the scavenge oil outlet as required bythe attitude of the blower.

BACKGROUND ART

The delivery of oil to components requiring lubrication and thereafterscavenging the oil is well known in the art.

A prior art search has revealed the following U.S. patents having somerelevancy to scavenging of lubricating oil: Jones Pat. No. 1,958,145;Weeks Pat. No. 2,503,016; Syrovy Pat. No. 3,025,672; Bill et al Pat. No.3,075,349; Luenberger Pat. No. 3,075,690; Venable Pat. No. 3,378,104;Kievit Pat. No. 3,442,444; DeLisse Pat. No. 3,618,710; and DeSalve Pat.No. 4,285,632.

Generally, the foregoing patents relate to scavenge oil systems withoutany reference to scavenging oil from a housing which may operate inseveral different attitudes, by use of a scavenge pump which only pumpsoil when required by the attitude of the housing. The Venable Pat. No.3,378,104 discloses an air-oil separator for use in gas turbine enginesand makes reference to operation of the aircraft in a steep climb whichwould change the attitude of the mechanism. The patent refers toscavenging oil during a steep climb or dive of the aircraft to preventflooding of the gearbox. However, the solution achieved in this patentis by oversizing a scavenge pump and there is oil in the gearbox at alltimes that can cause churning losses.

The foregoing prior art does not disclose a scavenge oil system for amechanism, such as a blower associated with a gearbox, whereinlubricating oil is supplied from the gearbox and the scavengedlubricating oil is returned to the gearbox either by gravity flow to thegearbox or, in certain attitudes of the mechanism, by pumping of the oilby a scavenge pump which is not effective to pump oil in those attitudeswhere the scavenged oil can flow by gravity to a scavenge pump outlet ofthe mechanism. When the blower is mounted on top of the gearbox, theflow from the scavenge oil outlet back to the gearbox can be by gravity.If the blower is mounted at the side of the gearbox, the scavenge oiloutlet of the blower can be connected by passage means to a scavengepump within the gearbox.

DISCLOSURE OF THE INVENTION

A primary feature of the invention is to provide a scavenge oil systemfor scavenging oil from a housing having components requiringlubrication and which is operable in different attitudes by associatinga scavenge pump with driven mechanism in the housing and locating thescavenge pump to be effective in pumping oil from the housing only inattitudes of the housing wherein the lubricating oil cannot reach ascavenge oil outlet by gravity flow.

In accomplishing the foregoing, the housing, which may be a housing fora blower, has a driven shaft and components within the housingassociated with the driven shaft as well as a dynamic face seal whichrequire lubrication. The housing has a scavenge oil outlet at the bottomthereof whereby, in most attitudes of the housing, the lubricating oilcan flow by gravity to the scavenge oil outlet and then return to agearbox associated with the housing either by continued gravity flow orby being pumped to the gearbox by a scavenge pump in the gearbox. Thescavenge oil outlet is effective in a normal attitude of the housingwherein the axis of the driven shaft is horizontal and is also effectivein other attitudes, such as attitudes where the housing has rotatedwithin a predetermined angle about the axis of the driven shaft and alsoa nosedown attitude, up to approximately 45°. The scavenge oil outlet isnot effective for outflow of oil when the housing is in a nose-upposition or attitude wherein the driven shaft is vertical. In thisattitude, there is a part of the housing lower than the scavenge oiloutlet, which is the rear of the housing when the housing is in theaforesaid normal attitude. A scavenge pump is located within the housingat the rear thereof having an impeller connected for rotation with thedriven shaft. In the aforesaid nose-up attitude, the scavenge pump ispositioned within the oil collecting in the rear of the housing and canpump this oil out of the housing through suitable passages.

Since the scavenge pump is only effective to pump oil in the aforesaidnose-up attitude, the amount of power used by the scavenge pump is verysmall. The pump runs dry when the housing is in the other atti- tudes.

An object of the invention is to provide a new and improved scavenge oilsystem for scavenging oil from a housing that may be operable in severaldifferent attitudes, including, the use of a continuously rotatingscavenge pump which is only effective to pump oil from the housing inless than all of the attitudes of the housing and which runs dry in theother attitudes to minimize power consumption.

Another object of the invention is to provide a scavenge oil system, asdefined in the preceding paragraph which has very low weight and lowcost and which is of compact size and highly reliable.

A further object of the invention is to provide a scavenge oil systemfor a blower for scavenging oil from a blower housing having a drivenshaft and which provides for gravity flow of oil to a scavenge oiloutlet or alternatively pumping oil from the blower housing by ascavenge pump in at least one attitude of the blower and which is of acompact size and low weight and cost. The compactness is achieved byhaving the scavenge system packaged inside the blower with cored flowpassages in the blower main housing and the scavenge pump housingintegrated therewith. The scavenge oil system has very low weight, sincethe cores are integrated into the blower housing, rather than the flowpassages being defined by separate elements and this constructioncontributes to the low-cost. The scavenge pump is driven by the drivenshaft of the blower and is of a simple construction having a radialblade impeller with large flow capacity and with the scavenge pump beingconstructed of a light composite material and very small.

The scavenge oil system is highly reliable because of its dependenceupon gravity and the lack of any use of moving parts, except for thescavenge pump which is mounted directly on the driven shaft of theblower.

An additional object of the invention is to provide a scavenge oilsystem for scavenging oil from a housing which rotatably mounts a shaftby bearings and has a gear mesh therein for rotating the shaft and ascavenge oil outlet at the bottom of the housing, with the improvementthereto which comprises a scavenge pump in the housing at the rearthereof and having an inlet above the scavenge oil outlet and alsohaving a scavenge pump outlet and passage means connected to saidscavenge pump outlet for discharge of pumped oil.

Still another object of the invention is to provide a scavenge oilsystem, as defined in the preceding paragraph wherein the scavenge pumphas an impeller connected to the shaft in the housing to be driventhereby.

A further object of the invention is to provide a blower having a casinghaving a gas flow passage, a blower housing positioned within said gasflow passage, stator means mounting said blower housing to said casing,a rotatable shaft mounted within said blower housing and having bladessecured thereto, bearing means rotatably mounting said rotatable shaftin the blower housing, drive means for said rotatable shaft extendingthrough said stator means, means including a passage through said statormeans for delivering lubricating oil to said bearing means, andscavenging means including a scavenge pump and a scavenge oil outlet forscavenging lubricating oil from the blower housing in all operationalpositions thereof either by gravity flow to the scavenge oil outlet orby gravity flow to the scavenge pump when the lubricating oil does notflow by gravity to the scavenge oil outlet.

Additional objects of the invention are to provide a blower, as definedin the preceding paragraph, wherein the scavenging means includes apassage through the stator means and with passages formed in the wallsof the blower housing which communicate with the passage through thestator means and with said passages being formed by cores in thehousing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a central plan section of a fan or blower usable as an inletparticle separator and shown in association with a gearbox;

FIG. 2 is a vertical section, taken generally along the line 2--2 inFIG. 1;

FIG. 3 is a sectional view, taken along the line 3--3 in FIG. 2;

FIG. 4 is a central vertical section of an oil cooler blower shown inassociation with a gearbox; and

FIG. 5 is a plan section, taken generally along the line 5--5 in FIG. 4.

BEST MODES FOR CARRYING OUT THE INVENTION

One embodiment of the scavenge oil system is shown in FIGS. 1-3associated with a blower operable as an inlet particle separator.

A casing, indicated generally at 10, has joined sections 11 and 12 whichprovide an air inlet 15 to a flow passage leading to an air outlet 16,with the airflow passage being generally annular and defined between theinterior of the casing 10 and a blower housing, indicated generally at20, positioned within the casing and integral therewith by integrallycast stators, two of which are shown at 22 and 24, respectively. Agenerally conical hub 26 is rotatable relative to the blower housing 20and carries a plurality of blades, two of which are shown at 28 and 30for rotation within the airflow passage within the casing.

The blower is shown in FIG. 1 in association with a gearbox 32,indicated by broken line and extends from the side thereof. The gearboxhas a gearbox scavenge pump (not shown) and also gearing (not shown) forimparting rotation to a drive means including a drive shaft 34 whichextends through a passage 36 in the stator 24 and which is operablethrough gearing to rotate a rotatable blower shaft 38 in the blowerhousing 20. More particularly, the drive shaft 34 is splined at 40 to agear 42 meshing with a gear 44 which is keyed at 46 to the blower shaft38. The gear 42 is rotatably mounted in bearings 50 and 52, supported byintegral structural elements of the blower housing and the blower shaft38 is supported by bearings 54 and 56 mounted in a tubular blowerhousing element 58 having integral therewith the components forsupporting the bearings 50 and 52 and an integral frusto-conical member59 which forms part of the blower housing by connection to the part 60thereof at several circumferential locations, one of which is shown at62.

The hub 26 is attached to a reduced diameter end 64 of the blower shaft38 by fastening structure 66 and a dynamic face seal 68 seals theinterior of the blower housing 20 from the exterior thereof and,specifically, from the underside of the hub 26.

As well known in the art, it is necessary to provide lubricating oil tothe spline 40 and the bearings 50, 52, 54 and 56 as well as to the meshbetween the gears 42 and 44 and the dynamic face seal 68. Thislubricating oil is supplied to these components from oil pumped from thegearbox 32 which flows through a passage 70 and which communicates withpassages, not shown, for delivering lubricating oil to these components.The lubrication of these components is shown more particularly in theembodiment of FIGS. 4 and 5. It is necessary to scavenge this oil fromthe blower housing and, in the embodiment of FIGS. 1-3, there is ascavenge oil outlet 75 at the bottom of the blower housing having acommunicating passage 76, with an outlet end 77 which communicates witha passage 78 leading to the gearbox 32, whereby a gearbox scavenge pump(not shown) within the gearbox can pump oil from the bottom of theblower housing 20.

This scavenging of oil is effective, with the blower housing 20 in anumber of different attitudes, including a normal attitude wherein therotatable shaft 38 is horizontal as well as in attitudes where theblower housing is nose-down up to an angle of 45° and may be inrotational attitudes of up to ±30° rotation around the axis of theblower shaft 38. The blower housing may also have an attitude where itis in a 90° nose-up position with the blower shaft 38 extendingvertically and with air flowing downwardly from the inlet 15 to theoutlet 16. In this last-mentioned attitude, the scavenge oil outlet 75is at a higher elevation than portions of the blower housing which willreceive lubricating oil by gravity flow. In order to scavenge this oil,a scavenge pump, indicated generally at 80, is positioned at an end ofthe blower shaft 38 and at the rear of the housing 20.

The scavenge pump 80 has a pump housing 82 integral with the blowerhousing section 60 with an inlet 83 to a radial blade impeller 84connected by means 85 to an end of the blower shaft 38. A scavenge pumpoutlet 86 connects to a passage 87 having an outlet 88 adjacent thescavenge oil outlet 75 whereby oil pumped by the scavenge pump 80 isdelivered to the scavenge oil outlet 75 and the oil is scavenged by thescavenge pump in the gearbox. Operation of the scavenge pump in the 90°nose-up attitude can be visualized clearly. It will be understood thatthe view of FIG. 2 would be rotated 90° clockwise and the view of FIG. 3rotated 90° counterclockwise from the positions shown to have thescavenge pump 80 lowermost in the views.

The passage 87, as well as the passage 76, are integral with the wall ofthe blower housing and are cored passages, to thus avoid added piping toprovide the passages.

In the embodiment of FIGS. 4 and 5, an oil cooler blower is illustrated,which is generally of the same construction as the blower illustrated inFIGS. 1 to 3, and the comparable parts in the two embodiments have beengiven the same reference numeral, with a prime affixed thereto, in theembodiment of FIGS. 4 and 5. In the embodiment of FIGS. 4 and 5, theblower is mounted on top of the gearbox 32' and, thus, the passage 36'through the stator 24' through which the drive shaft 34' extends alsodefines a scavenge oil outlet whereby in most attitudes of the blower,lubricating oil can flow by gravity to the passage 36' and, thus, returnto the gearbox 32'. The blower faces oppositely as compared to FIGS. 1-3with the inlet 15' on the right.

The lubricating oil supplied from the gearbox through the passage 70'flows through a series of cored passages 100, 101, and 102, as well as aconnector 103, with restricted flow passages 105, 106, and 107communicating with the passage 102 delivering lubricating oil to thedynamic face seal 68', and the bearings 54' and 56', respectively.

As in the embodiment of FIGS. 1 to 3, when the blower is in a 90°nose-up attitude, the passage 36' is above the lowermost part of theblower housing 20' whereby lubricating oil cannot flow by gravity backto the gearbox 32'. The scavenge pump 80' , which is located at the rearof the blower housing 20' is, in this attitude, located where thelubricating oil will flow by gravity and the oil can enter the scavengepump inlet 83' and a scavenge pump outlet connects with a cored passage110 formed in the wall of the blower housing 20' which has an outlet end111 opening to the gearbox 32'.

In both of the disclosed embodiments, lubricating oil can be scavengedby gravity flow of the oil to a scavenge oil outlet at the bottom of theblower housing in most attitudes of the blower housing. The blowerhousing can assume an attitude whereby oil will not flow by gravity tothe scavenge oil outlet, but will flow to a part of the housing at alower level. In both embodiments, a scavenge pump is located to pump theoil which flows to that lower level. The scavenge oil system disclosedresults in minimizing power losses, since the scavenge pump 82, 82' runsdry when the blower is in most of its attitudes and only a small amountof power is used when the pump is pumping oil. Additionally, most of therotating components are kept out of the lubricating oil to minimizechurning losses and the velocity of the oil in the scavenge lines iskept low because of the large diameter cored passages to reduce pressurelosses.

The scavenge oil system results in minimum blockage to the airflow pathfrom the inlet 15' to the outlet 16' because of the scavenge linespassing through the stators 24 and 24'.

The scavenge oil system does not add to the compact size of the blowerhousing, since it is packaged inside the blower and the scavenge pumphousing and cored passages are integrated with the blower housing. Thescavenge oil system is reliable because the lubricating oil flows bygravity at all times, either to a scavenge oil outlet or to a locationwhere the scavenge pump is operable and with the pump being mounted onthe blower shaft there is no rubbing contact between the pump and theblower housing. The scavenge oil system is of low weight and low cost,since the cored passages are integrated into the blower main housing,with the scavenge pump being driven by the blower shaft and the scavengepump being made of a light composite material and very small. The pumphas a radial blade impeller which, thus, enables use of the impeller,regardless of the direction of blower shaft rotation and with thescavenge pump having large flow capacity.

We claim:
 1. A blower having a casing having a gas flow passage, ablower housing positioned within said gas flow passage, stator meansmounting said blower housing to said casing, a rotatable shaft mountedwithin said blower housing and having blades secured thereto, bearingmeans rotatably mounting said rotatable shaft in the blower housing,drive means for said rotatable shaft extending through said statormeans, means including a passage through said stator means fordelivering lubricating oil to said bearing means, and scavenging meansincluding a scavenge pump and a scavenge oil outlet for scavenginglubricating oil from the blower housing in all operational positionsthereof either by gravity flow to the scavenge oil outlet or by gravityflow to the scavenge pump when the lubricating oil does not flow bygravity to the scavenge oil outlet.
 2. A blower as defined in claim 1wherein the scavenge pump is connected to said rotatable shaft.
 3. Ablower as defined in claim 1 wherein said scavenging means includes apassage through said stator means.
 4. A blower as defined in claim 3wherein said scavenging means includes passages formed in the wall ofthe blower housing which communicate with the passage through saidstator means.
 5. A blower as defined in claim 1 and positionable indifferent attitudes, said rotatable shaft and drive means extendinghorizontally with the scavenge pump at the rear of the blower housingwhen the blower is in one attitude and said scavenge oil outlet being atthe bottom of the blower housing, said blower being positionable in asecond attitude with the rear of the blower housing lower than thescavenge oil outlet and passage means in the wall of the blower housingfor delivering scavenged oil from the scavenge pump to the scavenge oiloutlet when the blower is in said second attitude.
 6. A blower asdefined in claim 5 wherein said scavenge oil outlet is defined by acored passage in the wall of the blower housing.
 7. A blower as definedin claim 5 wherein said scavenge pump has a pump housing integral withsaid blower housing, a radial blade impeller rotated by said rotatableshaft, and an opening in said pump housing communicating the rear of theblower housing with the radial blade impeller.
 8. A blower as defined inclaim 1 and positionable in different attitudes, said rotatable shaftextending horizontally and said drive means extending vertically withthe scavenge pump at the rear of the blower housing and said scavengeoil outlet being at the bottom of the blower housing adjacent said drivemeans when the blower is in one attitude, said blower being positionablein a second attitude with the rear of the blower housing lower than thescavenge oil outlet, and passage means in the wall of the blower housingfor delivering scavenged oil from the scavenge pump to the scavenge oiloutlet when the blower is in said second attitude.
 9. A blower asdefined in claim 8 wherein said scavenge pump has a pump housingintegral with said blower housing and a radial blade impeller rotated bysaid rotatable shaft.